In the related art, a power motor, a transmission, a transmission shaft, and a vehicle axle are all disposed separately, and power is transmitted stage by stage, resulting in a lot of transmission sections, a long transmission link, low transmission efficiency, a large volume, and difficult arrangement. In particular, with regard to some agitator trucks, in order to satisfy requirements for high power, volumes of power motors and transmissions are usually relatively large, axles withstand large torque, and it is difficult to ensure connection strength between vehicle axles and transmissions. Therefore, there is room for improvement.